<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        body {
            width: 100px;
            height: 100px;
            display: flex;
        }

        div {
            text-align: center;
            font-style: 100px;
            line-height: 100vh;
        }

        .left {
            background-color: powderblue;
            width: 200px;
            flex: 1;
        }

        .right {
            background-color: purple;
            flex: 4;
        }
    </style>
</head>

<body>
    <div class="left">左</div>
    <div class="right">右</div>
</body>

</html>